Shroud

Shroud is a term used to denote the ability of the Jem'Hadar to "cloak" themselves to avoid capture, injury, and to confound their opponents, similar to a more advanced form of active camouflage. (DS9: "The Jem'Hadar")

A shrouded Jem'Hadar would seem to vanish into thin air, although this was not the case. When they used the shroud, the immediate area in which they stood would turn dark, then become almost perfectly transparent. Only the most observant individuals could see the slight shifts in light as the Jem'Hadar moved about in their shrouded condition. (DS9: "To the Death")

Like all Jem'Hadar functions, the ability to shroud was regulated by the presence of ketracel-white. Jem'Hadar who endured prolonged periods without the drug eventually lost their ability to shroud. Such a degeneration in their abilities signaled severe withdrawal from the addiction to ketracel-white, and indicated that death was not far off. (DS9: "Rocks and Shoals")